Blade attachment means for saber saw assembly

ABSTRACT

Means for attaching a saber saw blade to the reciprocating portion of a saber saw assembly, wherein the blade can be releasably secured to the reciprocating portion which has means biased in a manner to hold the blade in such position. A number of embodiments of the attachment means provide for quick coupling and release of a saber saw blade to the assembly. In one group of embodiments, a blade holding means utilizes a torsion spring and in a second group of embodiments, the attachment means utilizes a compression spring. The support for the attachment means can be provided with any one of a number of improved abutments for engaging a workpiece. The support can be provided with means for moving the blade in a direction away from the kerf in a workpiece.

United States Patent n91 Hoffman [111 3,823,473 July 16,1974

[ BLADE ATTACHMENT MEANS FOR SABER SAW ASSEMBLY [76] Inventor: Simon J.Hoffman, P.O. Box 748,

Saratoga, Calif. 95070 22 Filed: Apr. 20, 1973 21 App1.No.:353,146

Related US. Application Data [62] Division of Ser. No. 97,425, Nov. 9,1970, Pat. No.

[52] US. Cl 30/338, 30/339, 30/392, 83/750, 83/698, 279/97 [51] Int. ClB27b 19/08 [58] Field of Search 30/223, 224, 329, 338,

[56] References Cited UNITED STATES PATENTS 104,613 6/1870 Mason 83/6982,101,362 12/1937 Davidson 83/697 X 2,895,514 7/1959 Wright 30/394 Wardet al. 30/329 X Daniel, Jr. 279/81 Primary Examiner-Roy Lake AssistantExaminer-James F. Coan [5 7] ABSTRACT Means for attaching a saber sawblade to the reciprocating portion of a saber saw assembly, wherein theblade can be releasably secured to the reciprocating portion which hasmeans biased in a manner to hold the blade in such position. A number ofembodiments of the attachment means provide for quick coupling andrelease of a saber saw blade to the assembly. In

one group of embodiments, a blade holding means utilizes a torsionspring and in a second group of embodiments, the attachment meansutilizes a compression spring. The support for the attachment means canbe provided with any one of a number of improved abutments for engaginga workpiece. The support can be provided with means for moving the bladein a direction away from the kerf in a workpiece.

1 Claim, 38 Drawing, Figures PATENTEDJULIBIBM 3,823,473

saw u or 5 FIG. IOc

BLADE ATTACHMENT MEANS FOR SABER SAW ASSEMBLY in which a saber saw bladeis attached to the adaptor leaves much to bedesired because conventionalstructures for accomplishing this purpose are quite complicated and areexpensive to produce. Moreover, such I structures are difficult to use,a factor which causes problems for hobbyists and others who may not havethe dexterity required to connect a saber saw blade to such structures.

The present invention is directed to blade attachment means for anadaptor of the type utilized with a conventional hand" drill powersource wherein a saber saw blade can be quickly and easily connected tothe adaptor in an operative position and then, after use, easily removedfrom the adaptor so that any individual having a minimum of skill withtools can use the saber saw bladein combination with the power drilldevice and the adaptor itself. The simplicity of the presentinventioneliminates the problems due to the complexity of the structureswhich have heretoforebeen used. The attachment means of the inventioncan be made from inexpensive materials, has a long operatinglife, andcan be used with any adaptor so long as the latter has structure whichreciprocates in the way in which a saber saw blade is normally to beused.

Another aspect of the invention is the provision of improved,interchangeable abutment means for the front end of the adaptor. Oneform of such abutment means allows for the'adaptor to be set at anyangletto the workpiece. Such feature allows the saber saw assembly to bequickly and easily used for mitering workpieces. Other forms of theabutment means include one in which rollers are used for rollingengagement with a workpiece during the cutting action of the saber sawblade attached to the adaptor, and one in which a spherical projectionis adapted to surround the blade and to engage a workpiece at any one ofa number of different angles so that the workpiece can still be cut eventhough it has an irregular outer surface.

Another feature of the invention includes a mounting for the bladeattachment means wherein the path of the blade is at an angle withrespect to the longitudinal axis of the blade itself. This featureassures that during a portion of each complete cycle of reciprocation ofthe blade, the cutting teeth of the blade will tend to move away fromthe kerf in the workpiece to thereby facilitate the cutting" actions Theprimary object of this invention is to provide improved blade attachmentmeans for a saber saw-assembly of the .type utilizing a conventionalhand drill power source and an adaptor connected thereto wherein theattachment means is simple and rugged in construction, utilizes springmeans for biasing certain parts into positions wherein a saber saw bladeis positively held for reciprocating movement, and thea'ttachment meanscan be in any one of a number of different forms to accommodate certainblade configurations.

Another object of this invention is to provide improved abutment meansfor the front end of a saber saw assembly of the type described tofacilitate the use of the assembly in cutting a workpiece of aparticular configuration while atthe same time, the various forms of theabutment can be utilized with any one of the embodiments of theattachment means of the invention.

Still another object of this invention is to provide an adaptor for anassembly of the aforesaid character wherein the' adaptor has means forreciprocating a saber saw blade along a path which is at an acute anglewith respect to the longitudinal axis of the blade so that during aportion of each reciprocating cycle of movement, the blade will tend tomove out of the kerf of the workpiece being cut to facilitate theover-all cutting action of the blade and thereby prolong the useful lifeof the blade itself.

Other objects of this invention will becomeapparent as the followingspecification progresses, reference being had to the accompanyingdrawings for illustrations of several embodiments of the invention.

In thedrawings:

FIG. 1 is a perspective view of a saber saw assembly utilizing aconventionalhand drill unit having an attachment for a saber saw bladetothe hand drill unit, and illustrating an adjustable abutment plate onthe front end of the assembly;

FIG. 2 is a side elevational view of the assembly of FIG. 1 showing theway the abutment plate rests on a workpiece to be cut;

FIG. 3 is a side elevational view of one form of the attachment showinga mountfor the blade to permit it to reciprocate;

FIG. 4'is a view similar to FIG. 2 but. showing a second embodiment ofan abutment on the front end of the assembly;

FIG. 4a is a side elevational view of the abutment guide of FIG. 4 whenthe same is separated from the assembly; 7

FIG. 5a is a view similar to FIG. 4a but showing a third embodiment ofan abutment;

FIG. 5b is a front elevational view of the abutment guide of FIG. 5alooking in the direction of line 5b--5b of FIG. 5a;

FlG.'6a is an end elevational view of one partof a first embodiment forthe blade attachment means of this invention;

FIG. 6b is a sideelevational view of the part of FIG. 6a;

FIG. is a side elevational view of a second part of the embodimentutilizing the part shown in FIGS. 6a and 61:,- i I 1 IG. 6d is an endelevational view of the part of FIG. 66; I t

FIG. 6e is a side elevational view of the first embodiment of theattachment means when the parts of FIGS. 6a-6d are assembled and a sabersaw blade is connected thereto;

FIG. 6f is a cross-sectional view taken along lines 6f-6f of FIG. 6e,showing the torsion spring used with the assembly;

, FIG. 6g is a fragmentary, side elevational view of a saber saw bladeused with the assembly of FIG. 6e;

FIG. 7a is a cross-sectional view of a second embodiment of the bladeattachment means utilizing a compression spring;

FIG. 7b is a cross-sectional view taken along line 7b-7b of FIG. 7a;

FIG. 70 is a fragmentary, side elevational view of an end portion of thesaber saw blade used with the embodiment of FIGS. 7a and 7b;

FIG. 8a is a side elevational view, partly in section, of anotherembodiment of the attachment means utilizing a torsion spring;

FIG. 8b is a cross-sectional view of the embodiment of FIG. 8a;

FIG. 80 is another cross-sectional view of the embodiment of FIG. 8alooking in a direction at right angles to the view of FIG. 8b;

FIG. 9a is a side elevational view of another embodiment of theattachment means utilizing a compression spring;

FIG. 9b is a cross-sectional view taken along line 9b9b of FIG. 9a;

FIG. 9c is a cross-sectional view taken along line 9c--9c of FIG. 9a;

FIG. 9d is a side elevational view of a portion of a saber saw blade tobe utilized with the embodiment of FIG. 10a is a side elevational viewof one part of another embodiment of the attachment means utilizing atorsion spring;

FIG. 10b is an end elevational view of the part of FIG. 10a;

FIG. 106 is a cross-sectional view of the embodiment using the part ofFIGS. 10a and 10b and showing a saber saw. blade connected thereto; 1

FIG. 11a is a cross-sectional view of still another embodiment utilizinga torsion spring;

FIG. 11b is a cross-sectional view taken along line lIb--llb of FIG.11a; I

FIG. Up is a fragmentary, side elevational view of the saber saw bladeutilized with the embodiment of FIGS. 11a and 11b.

FIG. 12a is a front elevational view of a further embodiment of theattachment means utilizing a torsion spring;

FIG. 12b is an end elevational view of a part of the structure of FIG.12a.

FIG. 120 is a side elevational view of the part of FIG. 12b;

FIG. 12d is a cross-sectional view of the attachment means of FIG. 12a;

FIG. l2e isa fragmentary, side elevational view of an end portion of asaber saw blade to be utilized with the embodiment of FIGS. 12a and 12b;

FIG. 13a is a side elevational view of another embodiment of the sabersaw blade attachment means utili zing a leaf spring and showing theblade removed therefrom;

FIG. 13b is a view similar to FIG. 13a but showing the blade coupled tothe attachment means; and

FIG. 130 is a cross-sectional view of the attachment means of FIGS. 13aand 13b.

The various embodiments of the blade attachment means of this inventioncan be utilized with any suitable power device which has a reciprocatingshaft or member. As will hereinafter be set forth, such embodimentswill, for purposes of illustration, utilize a reciprocating shaft. Theinvention is suitable for use with a hand drill 20 of conventionalconstruction and of the type shown in FIG. I wherein a housing 22 has ahandle 24 and carries a motor (not shown) therewithin for rotating adrill chuck 26. A conventional drill, when coupled with chuck 26, isrotated thereby upon actuation of the drill motor as is well known.

Instead of using a drill, an adaptor 28 can be utilized with chuck 26 toconvert rotational movement of the chuck into translational,reciprocatory movement. This reciprocating action is used to drive asaber saw blade coupled by an attachment means to adaptor 28.

Adaptor 28 may be of any construction but, for purposes of illustrationonly, it includes a housing 29 having a gear assembly (not shown) whichis rotated when a shaft coupled with chuck 26 is rotated. One form ofthe adaptor is shown in FIGS. 1, 2 and 4 and a second, slightlydifferentform of the adaptor is shown in FIG. 3. The essential difference betweenthe two forms of adaptors is that one mounts a blade at one side and theother mounts a blade at the opposite side. In view of such slightdifference, both forms will be described with reference to the samematerials.

The rotation of the gear assembly within housing 29 causes rotation of adisk 32 on a shaft 34 (FIG. 3) disposed transversely of shaft 30. A pin36 is radially, outwardly spaced from shaft 34 and is shiftably coupledwith a channel-shaped member 38 secured to a sleeve 40 which isshiftably mounted on a rod 42 in a recess 44 in the housing 29 ofadaptor 28. Thus, as shaft 30 is rotated by chuck 26, shaft 34 is causedto rotate to, in turn, cause rotation of pin 36. Member 38'is thuscaused to reciprocate with respect to housing 29 and the bladeattachment means 48 secured to member 38 causes a saber saw blade 50 toreciprocate with respect to adaptor 28.

The particular attachment means 48 shown in FIG. 3 includes a basemember 52 having a flat side face and a central pin 54 projectinglaterally from the side face, a flange 56 spaced laterally from the sideface at a location near one margin of base member 52 to confine one edgeof blade 50, and a second pin 58 near the margin of base member 52opposite to the margin having flange 56. Blade 50 has a hole forreceiving pin 54 and I a recessfor complemental engagement with pin 58.The blade thus can be secured to attachment means 48 and caused toreciprocate therewith relative to adaptor housing 29.

Attachment means 48 is constructed to position the longitudinal axis ofblade 50 at an acute angle with respect to the longitudinal axis of rod42. The angles are such that the rod and the blade diverge as the front,end of housing 29 is approached (FIG. 3). In this way, the blade, as itreciprocates, will tend to move out of the kerf in a workpiece 60 as itmoves forwardly of the adaptor. This will have the effectof clearing theworkpieceduring such forward movement so that; when the blade ismovedrearwardly again, it properly engages the workpiece to cut the same.

Adaptor 28 can be provided with quick disconnect, interchangeableabutment means including a first shiftable abutment 62 for engaging aworkpiece in the manner shown in FIGS. 1 and 2 when it is desired tomiter the workpiece or otherwise cut the same at an angle. Abutment 62includes a plate-like member 64 having a flat surface 66 for engagingthe workpiece, the surface having a slot 68 through which blade 50extends.

A pair of rods 70 and 72 are pivotally secured to the base 74 of member64 and are shiftably received within parallel bores in aboss 76 onhousing 46. Rod 72 is externally threaded and coupled to a nut 80received within a notch 82 which intersects the bore which receives rod72. Thus, by rotating nut 80 in the proper direction, rod 72 can becaused to move further inwardly or outwardly of the bore as rod '70 isheld by set screw 78. Since rods 70 and 72 are pivotally coupled withbase 74, the angularity of member 64 can thereby be varied with respectto blade 50.

FIG. 2 illustrates two operative positions of adaptor 28. One position,shown in full lines, illustrates member 64 at an angle with respect tothe workpiece so that blade 50 can provide a mitering effect. The secondposition, shown in dashed lines, illustrates how blade 50 isperpendicular to the workpiece.

Another embodiment of the abutment is shown in FIGS. 4 and 4a andincludes a pair of workpieceengaging rollers 84 mounted on opposite endsof a shaft 86 carried by abase 88 to which is secured a pair of rods 90and 92, the latter rod being externally threaded. The two rods areadapted to be shiftably received within the two bores of boss 76. Nut 80is adapted to become threadably connected with rod 92 in the mannerdescribed above with respect to abutment 62 so that both rods 90 and 92are secured to boss 76. Rollers 84 roll over the upper surface 94 of aworkpiece 60 as blade 50 cuts through the workpiece. The rollers therebyprovide a means by which a saber saw blade assembly is supported formovementwith minimum friction over a workpiece as the blade of theassembly cuts the workpiece.

Another embodiment of an abutment is shown in FIGS. Saand 5b andincludes a base 96 in the form of a shield having a workpiece-engagingprojection .98 on the front face 100 thereof. A slot 102 through base 96is provided to permit blade 50 to extend therethrough. Projection 98 hasa spherical outer surface so that the abutment can be used for roughcutting Within an 180 degree are while keeping the abutment close to theworking portion of the blade without blade breakage. Thus, the abutmentcan engage the irregular outer surface of a particular type of workpieceto thereby support the saber saw assembly as the blade of the assemblycuts the workpiece.

The abutment of FIGS. 5a and 5b is secured to adaptor 28 in the samemanner as the abutment of FIGS. 4 and 4a. To this end, a pair of rods102 and 104 are secured to base 96 and extend laterally therefrom. Rod102 is adapted to be secured in place by set screw 78 and rod 104 isexternally threaded so that it can become coupledwith nut 80. Thisconstruction permits the adjustability of base 96 with respect to thefront end of adaptor 28.

Another embodiment of the blade attachment means of this invention isillustrated in FIGS. 6a-6f and includes a first member 106, a secondmember 108, and a torsion spring 110 in the form of a coil surrounding alateral projection 112 rigid to member 108 (FIG. 6f). Member 106 has acentral opening 114 therethrough for receiving projection 112 as shownin FIG. 6f so that member 106 can rotate to a limited extend on member108. An annular countersunk region 115 in member 106 surrounding opening114 complementally receives member 108, the latter having opposedarcuate edges as shown in FIG. 6c. A pair of retainer strips 116 aresecured to member 106 and are spaced apart as shown I gagement with theflat faces 122 of member 108, the

latter having a recess 124 as shown in FIGS. 6c and 6f, for receivingthe portion 126 of a saber saw blade 128 with portion 126 being betweenopposed recesses or notches 130 in the edge margins of the blade.

Recess 124 of member 108 presents a pair of side faces 132 (FIGS. 6c and6]) which mate with recesses 130 of blade 128 whereby the blade iscoupled with member 108 and held thereby against movement in thedirection of the longitudinal axis of the blade. FIG. 6e illustratesblade 128 coupled to the attachment means including parts 106 and 108wherein the blade is held against lateral movement outwardly from faces122 of member 108 by retainer strips 11.6.

Member 108 has a shaft or member 134 which reciprocates in the directionof arrow 136 (FIG. 60). Shaft 134 is coupled in any suitable manner toprojection 112 and is adapted to be coupled in any suitable manner to apower drive such as to channel member 38 or sleeve 40 (FIG. 3) ofadaptor 28.

Coil spring 110 surrounds projection 112 and has one end 138 coupledwith member 106 through a hole 140 (FIG. 6b). The opposide end 142 ofthe spring is received within a bore in projection .112 (FIG. 6f). Thespring biases member 106 in a counterclockwise sense relative tomemberl08 when viewing FIG. 6ejThus, the spring normally has a restoringforce in the form of a torque on member 106.,

In use, .blade 128 is coupled with the attachment means shown in FIG. 6eby rotating member 106 in a counterclockwise sense until the edges 144of retainer strips 116 (FIG. 62) areessentially parallel with side faces132 of recess 124 (FIGS. 6c, 6d and 6]). The spacing between edges 144then permits blade 128 to be moved into recess 124 so that side faces132 complementally engage within recesses 130 of blade 128. Then, member106 is released, causing spring 110 to rotate member 106 in acounterclockwise sense when viewing FIG. 6e. When this occurs, retainerstrips 116 move into the full line positions of FIG. 6e wherein theyconfine the blade against movement laterally of and outwardly fromrecess 124. Thus, the blade is releasably coupled to member 108 and willreciprocate therewith upon reciprocation of shaft 134. The blade isremoved by reversing the above process.

Another embodiment of the blade attachment means is shown in FIGS. 7aand 7b and includes a shaft having an extension 152 provided with abladereceiving slot 154 in the outer end thereof. Shaft 150 is adaptedto be secured in any suitable manner to a power device so that the shaftcan reciprocate in. the direction of arrow 156 (FIG. 7a). Thus, shaft150 could, for example, be coupled with channel member 38 or sleeve 40of FIG. 3. l

A sleeve 158 surrounds extension 152 and is coupled thereto by a pin 160which is transverse to the longitudinal axis of extension 152 andprojects into diametrically opposed slots 162 in sleeve 158. A coilspring 164 surrounds extension 152 and is under compression between oneend face 166 of sleeve 158 and an annular shoulder 168 on shaft 150. Thespring biases sleeve 158 to the left when viewing FIG. 7a.

Sleeve 158 has a first cylindrical surface 170 which is only slightlylarger in diameter to the cylindrical outer surface of extension 152, asecond doubled cam surface 172 which flairs outwardly as the outer endof the sleeve 158 is approached, and a third cylindrical surface 174 atthe outer end of sleeve 158..

Extension 152 is provided with a first bore 176 which receives a pin 178having a head 180 provided with a convex outer surface 182. The pinprojects into slot 154 and is biased outwardly of the slot by a coilspring 184 surrounding the pin and disposed in bore 176.

Extension 152 has a second bore 186 into which is disposed a ball 188capable of engaging a blade in slot 154 when sleeve 158 is in theposition shown in FIG. 7a.

FlG. 7c illustrates an end portion of a blade 190 adapted for use withthe attachment means of FllG. 7a. Blade 190 has a hole 192 therethroughfor receiving pin 178 and a recess or notch 194 for complementallyreceiving a portion of pin 160. Pin 178 and ball 188 are held in theposition shown in FIG. 7a'by surfaces 170 and 172, respectively, yet thepin and the ballcan move outwardly of and laterally away from slot 154when sleeve 158 is moved to the right when viewing FlG. 7a against thecompression force of spring 164..

In use, sleeve 158 is first moved to the right when viewing FIG. 7a.This will position surface 172 in alignment with bore 176, therebypermitting pin 178 to move out of slot 154 under the influence of thebias force of spring 184. Similarly, ball 188 can move away from slot154 since surface 172 will become more completely aligned with bore 186then is shown in FIG. 7a.

Blade 190 is then inserted into slot 154 so that hole 192 is alignedwith pin 178 and recess 194 receives pin 160. Then, sleeve 158 isreleased, whereupon surface 172 cams pin 178 inwardly with respect toslot 154 until surface 170 overlies head 180 as shown in FllG. 7a.Similarly, ball 188 is moved into frictional engagement with theopposite side of the blade. The blade is then held at least at twopoints, namely, at hole 192 and at recess 194. The blade cannot beremoved from the slot nor can it move in the plane of the slot. Shaft150 can then be reciprocated to, in turn, cause reciprocation of theblade in the slot. To remove the blade from the attachment means, theabove steps are repeated.

Another embodiment of the attachment means utilizng the torsionprinciple is shown in FIGS. Zia-8c and includes a shaft 200 having ablade-receiving slot 202 extending inwardly from one end face 204thereof. An annular flange 206 surrounding the entrance to slot 202 isused as an abutment for engaging one end of a sleeve 208 mounted on andsurrounding shaft 200.. A coil spring 210 surrounding shaft 200 has oneend coupled to the shaft and the opposite end 212 secured in anysuitable manner to sleeve 208. The spring is normally twisted so that itapplies a torque to sleeve 208 in a counterclockwise direction whenviewing FlG. 8c.

The inner surface of sleeve 208 has a pair of diametrically opposed camsurfaces 214 and 216 which extend axially of the sleeve. Surface 214 isadapted to engage a blade-holding member, such as a ball 218., carriedin a bore 220 in shaft 200 (FIG. 812). Surface 216 is adapted to engagea pair of spaced blade-holding members, such as balls 222 and 224,disposed in transverse bores 226 and 228, respectively, in shaft 200,

bores 226 and 228 being staggered with respect to bore 220 as shown inFIG. 8b.

Shaft 200 is adapted to be secured to a power drive in a'manner suchthat the shift is capable of reciprocating in the direction of arrow 230(FIG. 8a). For example, shaft 2 may be coupled to channel member 38 orsleeve 40 of adaptor 28 shown in FIG. 3.

In use, sleeve 208 is rotated slightly so that the large diameterportions of surfaces 214 and 216 are aligned with the bores containingballs 218, 222 and 224. This will allow the blade-holding members to bemoved a short distance in directions away from slot 202. A saber sawblade having recesses for at least partially receiving the balde-holdingmember is then inserted into slot 202 as sleeve 208 is held withsurfaces 214 and 216 in the aforesaid positions. The blade is moved intothe slot until it abuts the inner end of the slot. Thereupon, sleeve 208is released, thereby returning surfaces 214 and 216 to the positionshown in FIG. 80. When this occurs, the surfaces cam the blade-holdingmembers 218, 222 and 224 inwardly with respect to slot 202 so that suchmembers at least partially enter respective recesses of the blade andhold the same against movement out of the slot. The width of the bladeis essentially equal to the diameter of the cylindrical inner surface ofsleeve 208 so that the sleeve confines the blade against any movement inthe plane of slot 202 while the members substantially prevent anymovement of the blade out of the slot. The blade is removed by reversingthe above steps.

Another embodiment of the attachment means for a saber saw blade isshown in F165. 9a-9c and includes a shaft 240 adapted to be secured to apower device so that the shaft can reciprocate in the direction of arrow242 (FlG. 9b). The shaft has a pair of spaced, parallel pins 244 securedthereto and projecting laterally therefrom. The outer ends of the pinsare received within a groove 246 on the inner surface of a sleeve 248which is biased to the left when viewing FTG. 9b by a coil spring 256surrounding shaft and being under compression. The sleeve is movable tothe right against the bias force of spring 256 so that the outer ends ofpins 244 can be exposed. in this way, a saber saw blade 258 having apair of holes 260 therein can'be coupled with pins 244.

To accommodate the end of blade 2.58, sleeve 248 has a transverse groove261 (FIG. 9c) by means of which the end of the blade can projectbeyondthe proximal end face of the sleeve.

in use, sleeve 248 is moved to the right when viewing FllG. 9b againstthe bias force of spring 256. When this occurs, the outer ends of pins244 are exposed and blade 258 can be moved onto the pins with the pinsbeing received within holes 260. Then, the sleeve is released and isallowed to move to the left when viewing FIG. 9b thereby releasablyconnecting the saber saw blade to pins 244. The blade cannot move offthe pins in a direction axially of shaft 240. Also, the configuration ofgroove 261 prevents lateral movement of blade 258 axially of pins M4. Tothis end, the inner surface 262 forming the inner extremity of groove261 is lflat and complementally engages the flat side of the blade,thereby preventing it from moving laterally of the adjacent side ofshaft 240. When it is desired to remove the blade, the above steps arereversed.

Still another embodiment of the blade attachment means of this inventionwhich utilizes the torsion principle is shown in FIGS. la-l0c andincludes a shaft 270 which is adapted to be coupled with a power drivein a manner such that the shaft is able to be reciprocated in thedirection of arrow 272 (FIG. 10c).

Shaft 270 has an externally threaded cylindrical portion 274 and aconical portion 276 which decreases in diameter as the outer end of theshaft is approached. Portion 276 has a blade-receiving slot 277 therein,the slot being open at the end of the shaft so that the end 281 of asaber saw blade 279 can be inserted into slot 277. End 281 is providedwith a pair of end marginal edges 283 (FIG. 10c) which have essentiallythe same taper as conical portions 276. Edges 283 also present a pair ofshoulders 285 on blade 279.

A sleeve 278 is threadably coupled with cylindrical portion 274 forrotation relative to shaft 270. Sleeve 278 has a slot 280 (FIG. 10a)therein which is alignable with slot 277, whereby end 281 of blade 279can be coupled to the shaft.

The inner surface 282 of sleeve 278 axially spaced from the internallythreaded portion thereof is tapered so as to be complemental to theouter surface of conical portion 276 of shaft 270. Thus, the innersurface decreasesin diameter as the annular end face 284 of sleeve 278is approached.

A coil spring 286 surrounds shaft 270 and has an end 288 coupled in anysuitable manner to an annular flange 290 on sleeve 278. The opposite end(not shown) of the spring is secured to the shaft in a manner such thatthe spring is under stress-and biases sleeve 278 in a counterclockwisewhen viewing FIG. 10b. Normally, slot 280 is perpendicular to slot 277as shown in FIG. 10b. Thus the end 281 of blade 279 cannot be insertedinto slot 277. Only when the slots are in alignment with eachother,-i.e., in the same plane, can a bladebe inserted into or taken outof slot 277.

In use, sleeve 278 is rotated in a clockwise sense when viewing FIG. 10bto bring slot 280 into alignment with slot 277. Then, end28l can beinserted into the slot so that end 281 of blade'279 is moved into thedashed line position thereof shown in FIG. 10c. Thereupon the sleeve 278is released, returning it to the position shown in FIG. 10b. The innersurface 282 of sleeve 278 will then prevent end 281 from being removedfrom slot 277. In this way, blade279 is releasably coupled to shaft 270.

A further embodiment of the blade attachment means of this inventionutilizing the torsion principle is shown in FIGS. 11a and 11b andincludes a shaft 300 which is adapted to be secured in any suitablemanner to a power drive so that the shaft can be reciprocated in thedirection of arrow 302 (FIG. 11a). The shaft has a blade-receiving slot304 therein which is open at the forward end face 306 of the shaft. Asleeve 308 is rotatably mounted on the outer surface of the shaft and isconfined thereon against movement to the left when viewing FIG. 1121 byan annular flange 310 integral with shaft 300. A coil spring 312 has oneend 314 secured to the sleeve and the opposite end (not shown) securedto the shaft. The spring is under stress and biases sleeve 308 in aclockwise direction when viewing FIG. llb.

Sleeve 308 has an internal cam surface 316 which normally engages anelongated retainer element 318 shiftably received within a bore 320extending transversely of and communicating with slot 304- Element 318has a convex outer surface 322 which engages cam surface 316. Theremainder of the interior of sleeve 308 is generally cylindrical so asto be complemental to the outer surface of shaft 300.

The shaft has a second bore 324 on the opposite side of slot 304. A coilspring 326 and a guide member 328 are disposed within bore 324. The tip330 of member 328 extends across slot 304 when there is no blade in theslot. However, the tip 330 is conical so that a blade inserted into slot304 will force member 328 inwardly of bore 324 against spring 326,thereby compressing the spring and thereby allowing tip 330 to move outof the slot 304 and into bore 324. Normally, however, cam surface 316,under the influence of spring 312, biases element 318 so that the innerend portion 332 thereof is received within slot 304. Thus, portion 332normally engages tip 330 and biases the latter into bore 324 sincespring 326 has a smaller restoring force than spring 312.

FIG. 11c illustrates a portion of a saber saw blade 334 for use with theattachment means of FIG. 11a.

Blade 334 has an opening 336 therethrough which is elongated and issubstantially complemental with portion 332 of element 318 except for apair of arcuate portions 338 at the center of opening 336 and theopposite sides thereof.

In use, sleeve 308 is rotated in a clockwise sense against the biasforce of spring 312 until the sleeve is in the position shown inFIG..l1b. This will allow spring 326 to bias member 328 out of bore 324to, in turn, cause tip 330 to engage portion 332 and force element 318in a direction out of slot 304. Blade- 334 is then inserted into theslot and the conical configuration of tip 330 allows the blade, to urgethe tip into bore 324 as the blade holds element 318 away from slot 304.The slot is inserted far enough so that member 328 is received in thecentral part of opening 336 so that member 328 serves to position theblade so that it can readily receive portion 332 of element 318 inopening 336 when sleeve308 is released'When the blade is so positioned,the sleeve is released, whereupon spring 312 rotates the sleeve .in aclockwise sense when viewing FIG. 11b. Cam surface 316 then urgeselement 318 radially in wardly, causing portion 332 to enter opening 336of blade 334. Member 328 once again moves into bore 324 and compressesspring 326. In this way, the blade is releasably connected to shaft 300and is prevented from moving out of slot 304. To remove the'blade, theaforesaid steps are reversed.

Another embodiment of the blade attachment means utilizing the torsionprinciple is shown in FIGS. l2a-l2d and includes a tubular shaft 350which is secured to a power drive in a manner such that the shaft can bereciprocated in the direction of arrow 352 (FIG. 12d). The shaft has acountersunkportion at the outer end thereof for receiving a sleeve-likemember 354 having a pair of diametrically opposed grooves 356 and 358 onthe inner surface thereof (FIG. 12b). Member 354 is disposed within thecountensunk end portion of shaft 350 and engages the annular shoulder360 of shaft 350 which limits the inward travel of member 354. Aresilient retaining ring 362 releasably holds member 354 within shaft350.

A coil spring 364 has one end 366 received within a hole in the side ofshaft 350. The opposite end 3620f spring 364 is received within a hole370 in the side of member 354. End 368 also extends through acircumferential slot 372 in shaft 350 whereby member 354 can rotate to alimited extent about the axis of shaft 350. Spring 364 is normally understress so that member 354 is biased in a clockwise sense when viewingFIG. 12a.

Member 354 has an inclined surface portion 374 at one end face thereofand an inclined surface portion 376 at the opposite end face. Thesesurface portions terminate at respective grooves 356 and 358 to presentrespective projections 378 and 380 which are adapted to be receivedwithin respective recesses 382 and 384 at the opposed side edges of asaber saw blade 386 (FIG. 12c) when the blade, after being receivedwithin grooves 356 and 358, is rotated about an axis coincident with theaxis of member 354. In this way, the blade becomes coupled with member354 and cannot move axially of the same since the blade is then out ofthe plane in which grooves 356 and 358 are disposed.

A blade retaining element 388 is swingably mounted on shaft 350 by a pin390 carried by a boss 392 rigid to the shaft at the end thereof, pm 398being transverse to the axis of shaft 350 and disposed near the outersurface thereof.

Element 388 has a pair of sides 394 and 396 which are spaced apart topresent a slot 398 therebetween. This slot is provided to allow blade386 to pass therethrough while at the same time, sides 394 and 396prevent rotation of the blade about the axis of shaft 350 when element388 is in the dashed line position of FIGS. 12a and 12d. A spring 400coupled with element 388 and with boss 392 biases element 388 in thedashed line position of FIGS. 12a and 12d.

In use, element 388 is first raised into the full line'position of FIG.12a and blade 386 is then inserted into member 354, specifically, intogrooves 356 and 358 thereof. The blade is then rotated in acounterclockwise sense when viewing FIG. 12a until projections 378 and380 are received within recesses 382 and 384 of blade 386. Theprojections frictionally engage the blade at the sides of respectiverecesses thereof and further rotation of the blade will tend to rotatemember 354 through a small arc in a counterclockwise sense when viewingFIG. 12a against the bias force of spring 364. The blade is rotateduntil it is aligned with slot 398, thereupon, element 388 is moved intothe dashed line position of FIGS. 12a and 12d, whereby the blade isreceived within slot 398 and sides 394 and 396 of element 388 hold theblade against rotational movement relative to shaft 350. Projections 378and 380, in turn, prevent movement of the blade out of member 354. Theblade can then be reciprocated with shaft 350. To remove the blade, theabove steps are reversed.

Another embodiment of the blade attachment means of the invention isshown in FIGS. 13a-l3c and includes a shaft 410 which is adapted to bereciprocated in the direction of arrow 412 (FIG. 13c). Shaft 410 can becoupled in any suitable manner to a power source to effect suchreciprocation. For example, the shaft can be connected to sleeve 40 orchannel member 38 of 12 FIG. 3.

Shaft 410 has a projection 414 to which is secured a disk 416 having apin 418 provided with a head 420 at the center of the disk. A leafspring 422 which is curved in the manner shown in FIG. 13c is providedwith a detent 424 near one end thereof, the detent being near the outerperiphery of disk 416. As shown in FIG. 13a, the disk has a notch forreceiving an end portion of the detent.

A blade 426 having a pair of openings 428 and 430 is adapted to becoupled with pin 418 and detent 424. Openings 428 and 430 are spacedapart by a distance such that, when the blade is coupled with theattachment means shown in FIG. 13b, pin 4l81is at one end of opening 413while the detent essentially fills opening 428. Thus, the blade isreleasably secured to the pin and the detent and cannot move off thesame until the detent is moved out of opening 428.

In use, blade 426 is moved in the direction of arrow 429 (FIG. 13a) ontodisk 416. Head 420 initially passes through the enlarged part of opening430 and continued movement of the blade will move pin 418 into thesmaller portion of opening 430- as the blade deflects spring 422 to movedetent 424 away from the blade. When pin 418 is aligned with the smallerportion of opening 430, detent 424 is aligned with opening 428. Spring422 then moves the detent into opening 428 and head 420 preventsmovement of blade 426 off pin 418.

To remove the blade, it is' necessary to deflect spring 422away from theblade to cause movement of the detent out of opening 428. The blade isthen moved to the right when viewing FIG. 13b so that head 420 becomesaligned with the larger portion of opening 430 of the blade. The bladecan then be moved away from disk 4l6'and off pin 418.

When the blade is attached as shown in FIGS. 13!) and 13c, shaft 410reciprocates to, in turn, reciprocate blade 426 in the direction ofarrow 432.. Shaft 410 is coupled to a support 434 having a slot 436therein through which projection 414 extends.

In the claims:

1. In a saber saw assembly for use with a saw blade having a pair oflongitudinally spaced holes therethrough near one end portion thereof: amember adapted to be reciprocated along a straight-line path; a pair oflongitudinally spaced pins projecting outwardly from one side of themember, said pins adapted to be inserted in the holes of the blade forcoupling said one end portion of said blade thereto; a sleeve carried bythe member for longitudinal movement into and out of ablade-holding-position and having groove means therein for receiving andholding said end portion of the blade on the pins; and means biasingsaid holding means into said blade-holding position thereof.

1. In a saber saw assembly for use with a saw blade having a pair oflongitudinally spaced holes therethrough near one end portion thereof: amember adapted to be reciprocated along a straight-line path; a pair oflongitudinally spaced pins projecting outwardly from one side of themember, said pins adapted to be inserted in the holes of the blade forcoupling said one end portion of said blade thereto; a sleeve carried bythe member for longitudinal movement into and out of a bladeholdingposition and having groove means therein for receiving and holding saidend portion of the blade on the pins; and means biasing said holdingmeans into said blade-holding position thereof.